Subjective and objective recollection–familiarity distinctions differentially engage default mode network–hippocampal systems: An fMRI meta-analysis and a unified framework

Description: Recollection–familiarity distinctions can be assessed subjectively using Remember–Know judgments or objectively through retrieval of task-defined contextual information. Although both approaches are widely used, the extent to which they recruit common neural systems remains unclear. To address this issue, an fMRI meta-analysis was conducted across 18 subjective and 18 objective studies matched for stimulus type, examining the contrasts Remember > Know and source-correct > source-incorrect. The subjective contrast showed stronger associations with the default mode network (DMN) and posterior hippocampus than the objective contrast. Because subjective judgments are effectively criterion-free, they can incorporate any retrieved information supporting recollection, whereas objective accuracy on a task-defined contextual feature may fail to capture spontaneously retrieved non-criterial details. This distinction suggests that subjective judgments are more sensitive to overall memory strength, accounting for stronger DMN–hippocampal engagement. Together with prior meta-analyses of novelty-based and item–item associative contrasts, these findings indicate that subjective and objective memory paradigms emphasize different aspects of episodic retrieval, as reflected in differential engagement of the DMN, the frontoparietal control network, and the hippocampus.